The present invention relates to a method for warning a driver of a motor vehicle of an obstacle present in a side area next to a side flank of the vehicle with the help of a driver assistance system. During a motion of the vehicle—forward or backward—the obstacle is detected by an ultrasonic sensor stationarily arranged on a vehicle bumper. The obstacle is detected before it leaves a detection area of the ultrasonic sensor and enters the side area next to the side flank of the vehicle. Furthermore, the present invention relates to a motor vehicle comprising a driver assistance system which is designed for performing such a method.
Driver assistance systems for warning the driver of an obstacle present in a side area next to the side flank of the vehicle are already known from the prior art. Also, it is prior art that obstacles can be detected by means of an ultrasonic sensor arranged on a vehicle bumper, a front bumper or rear bumper. The detection of obstacles using standard ultrasonic sensors—i.e. sensors located stationarily at the front or at the rear of the vehicle—is limited during sharp turns. Initially, an obstacle present in front of or behind the vehicle can be detected by the sensor. Even if the detected obstacle is initially not in the path of the car, it can become present in the path after the sensor loses touch with the obstacle, i.e. after the obstacle enters the side area next to the side flank of the vehicle. Then, the sensor can no longer monitor the obstacle, and a collision can occur between the vehicle and the obstacle.
The prior art faces this problem as follows: Document EP 1 447 271 A2 discloses a driver assistance system for monitoring an area close to a motor vehicle. This system comprises an ultrasonic sensor located on a side flank of the vehicle. Thus, a collision between the side flank and the obstacle can be prevented. The current position of the obstacle can also be tracked depending on the path of the vehicle determined by a path sensor. In order to prevent a collision with the obstacle, the system provides a warning signal tone or automatically brakes the vehicle. So, the obstacle is detected based on an ultrasonic sensor located on the side flank of the vehicle. However, not all vehicles are equipped with such a sensor.
Moreover, document JP 06189610 A describes a motor vehicle comprising an ultrasonic sensor located in the front of the vehicle. The adjustment of the sensor can be changed and regulated. Thus, the detection direction of the sensor can be changed together with the turning direction according to the steering angle.
Furthermore, document JP 2004 351 992 A discloses a driver assistance system for a motor vehicle. The system can compute a possible path of the vehicle depending on the current steering angle measured by a steering angle sensor. Thereafter, the system inclines one ultrasonic sensor in the opposite direction and one sensor in the same direction as the steering direction. Thus, obstacles can be detected which are present on the vehicle path.
So, in the prior art a sensor located at the side flank of the vehicle or a movable sensor is required for warning the driver of an obstacle present in the side area next to the side flank of the vehicle. Thus, it is a challenge to provide a method for preventing a collision between an obstacle and the side flank of the vehicle using only a single ultrasonic sensor located at the front or at the rear of the vehicle.
An object of the present invention is to provide a solution as to how a driver of a motor vehicle can be warned of an obstacle present in a side area next to a side flank of the vehicle using a standard ultrasonic sensor stationarily located at the front or at the rear of the vehicle.
This problem is solved—according to the invention—by means of a method with the features according to patent claim 1 as well as by means of a motor vehicle with the features of patent claim 15. Advantageous embodiments of the invention are subject matter of the dependent claims and of the description.